Rotary gold concentrator



Feb. 26, 1935. a CAVE 1,992,288

ROTARY GOLD CONCENTRA'I'OR Filed Jan. 27, 1934 2 Sheets-Sheet 1 Fig. 1

awe/whom D. B. Cave Feb-Q26, 1935. D. B; CAVE 1,992,288

ROTARY GOLD CONCENTRATOR Filed Jan. 27, 1934 2 Sheets-Sheet 2 I I f I I i I D. B. Cave Patented Feb. 26, 1935 ROTARY com) CONCENTRATOR 7 Daniel B. Cave, Lincoln, N ebr., assignor, by direct and mesne assignments, of one-third to Allen P. Furgason, one-third to Emery F. Ozenbaugh and Edgar Over-ton, and one-thirdto Paul V. Ashton,all,of Lincoln, Nebr.

Application January 27, 1934, Serial No. 708,684

2 Claims; (01. 209-44) My invention relates to rotary goldconcentrators, its primary object being the provision of a concentrator which will operate efiiciently in separating microscopic gold from goldbearing sand.

.15 Another object -is the provision of a slowly rotating drum so designed that it will materially increasethe distance through which the gravel must pass over-screens to separate'the gold from the sand. i

Another of my objects is the provision of a concentrator which will not only separate the gold and'gold ore from the sand butwhich will segregate the finer from the coarser particles for convenience in milling the ore.f I

Another of-my' objects is the provision of a' separator which is sodesignedas to almost entirely eliminateeddycurrente or :other disturbances in thewater having microscopic particles suspended therein. l

Having, in view these objects and others which will bepointed out in the following description, :I' will now refer to the drawings, in-which,

' Figure 1 is a view partly in elevation and partly in section showing my rotary-gold ore separa- .Figure 2 is a top plan-view of this same separa torj thel shieldbeing ,omittedto more clearly disclosethe drum. i Figure 3 is a cross sectional-viewofthe separator. I Figure?! is ar'fragmentary view of alportion of the drum showing particularly the means for transferring the sand from compartment to; comipartment. m w w Figure 5 is-aview in sectioned pe spective showa ing the pickup iscoop-at the intake-to the drum.

Figure 612. View, in perspective showing the .skimmer adjacent tothedischarge end of the Figure'fl .isauv-iew in'perspective showing the discharge mechanism t for discharging the spent sand-after. it has passed through'thedrum;

Figure 8 isa perspective, viewwith parts broken away ofithe feed troughofthe separator.

5 :Figures 5;6landflareaxiallyg aligned toshow 'the relative positions of the: parts with respect to eachhother and withrespect to the organization.

1 The mechanism includesa rotary drum which is mounted JonwashaftlO tobe driven through: a worm or similar gear 11. Thedrum consists of a 'p'luralityzof disks 12 which are rigidly secured to "the shaftlo and which are rigidly tied together iby'm'e'ans ofbolts, l3. Hoops 14 are secured to the disks 12" at theirperipheries. The entire drumis surrounded rrby. screens; through which the finer cally opposite discharge apertures 25.

apertures 25 are positioned-in. the first comparte I ment of the drum so that the slowrotation of the PATENT OFFICE? material may pass during the rotation of the I.

drum. The screens 15 are of fine mesh, the

- screenslB are of medium mesh while the screens l'lare sufficiently large in mesh to permit the passage of the coarsest ore particles in the sand. The drum is designed for slowrotation in a tank 18 I containing water. This tank-is divided into three compartments by means of the parts 19. The ore passing through the screens'15 will thus .fall into the first'compartment, the medium sizedore will fall into the second compartment and the coarsest of the ore will require millingbeforethe particles of gold can be separated from. it and this is true to some extent of the medium ore. The finestof the ore: can usually be treated without the preliminary milling. Thearrangement asabove described facilitates the separation of the difierent ores-and-simplifies the milling process. The arrange'ment-can, however, be extended by separating the ore into as many different grades .as might be desired.

The tank-18 is provided with a receivingcom- -partment 20int o which the,goldbearingsand-is deposited The pickup scoop 21is shown in Fig- Lu e 5 in operation in the receiving compartment scoop 21 and then permitted to,.drop. The shaft 10 is hollow at its ends but the middle portion of the shaft 1 0 is either solid or itis blocked off, from the hollow end portions. Since the scoop vis provided with two intakes 2 2, the hollow portionof the shaft must have a-septum24 to prevent the material from dropping through to the bottom intake. The pressure of the wet sand entering the 20. This scoop is securedtorotate with the shaft of the shaft which is providedwith two diametridrum will causethe material to. roll on the inner surface of the first screen 15 to separate the finest ment. For this purpose eachv disk provided with an opening 26, all oftheseopenings being in These alignment. Connecting each pair of disks 1.2 is

a baflle 27 which extends from the rearward edge of one aperture 26 to the forward edge of the next aperture 26. Bafiies 2'7 prevent the material The material is thus forced to travel the entire interior surface of the screen of one compartment before it can be discharged into the next adjacent compartment.

The material is thus passed along with the separation of its finest materials as it passes through each compartment in succession. The finer particles are deposited in the various compartments of the tank 18 so that by the time the last compartment of the drum is reached, the material has been not only reduced in quantity but nearly all of the valuble portions of the ore have been extracted from it. The material then is in condition to be discarded. The last compartment of the drum is provided with a skimmer 28 which continuously divides the material in that compartment. The skimmer .is provided with two diametrically opposite. apertures 29 communicating with similar apertures 3Ov in the discharge mechanism. This dischargemember is similar to compartments be the same.

the scoop 21 in that it is secured to a hollow-por tion of the shaft 10 to rotate therewith. The water and spent sand entering the aperture 30 are forced toward the axis of rotation and into the hollow portion at the discharge end of the shaft 10. This hollow portion is also provided with a septum 31 to prevent the falling of the spent sand to the opposite end of the discharge mechanism. The spent sand suspended in water is thus forced out through the hollow portion at the discharge end of the shaft 10. w

The drum is surrounded by a stationary shield or jacket 32 except for its top portion. This shield terminates in its lower portion in' a relatively narrow spout 33 for discharging the materials from thescreen into the water in the tank 18.

' As a result the rotation of the drum, even though slow, will set up. disturbing currents in the water but these currents cannot be communicated to the body of water in the tank 18. Owing to the extremely minute size of the particles of gold discharged through the screens, it is exceedingly important that no disturbingcurrents be set up in the water which would retard the settling of the gold particles in the'water.

The screens employed for this purpose are of exceedingly fine mesh and in some cases there is a tendency for. them to become clogged up. For

obviating this difiiculty I provide a rotary brush 34 which rests against the upper surface of the screen. The brush 34 is mounted on a shaft which is journalled at its ends in a support as shown in Figure 1. The rotation of the drum will thus be communicated to the brush which rotates in contact with the screen throughout its entire length to drop any particles which might tend to "clog theopenings in the screen.

It is desirable that the water level in the two The water is introduced into the receiving compartment and I have provided a structure as shown in Figure 8 for per 'mitting the flow of the water into the main chamher without permitting the flow of the goldbearing sand into the drum. The chamber wall 35 is apertured and another wall 36 is inserted in the chamber 20 underneath the bearing of the shaft 7 10. The wall 36 is also apertured. The-twewails 35 and 36 are spaced apart and the space between themis filled with gravel to function as a filter for preventing the flow or anything but water The water thus readily seeks its level in both chambers. 1 a

In operation, power is suppliedthrough the worm drive to the shaft 10 and the cam 'rtment 20 receives the goldbearing sand. We also is added to keep at least part of this sand suspen sion. The pickup scoop forwards the mstesst into the first compartment from whence it is dis-f charged into the next compartment after one complete revolution ofthe drum. At the same time additional material passes into the first compartment to'take the place of that which is discharged. After a sufiicient number of revolutions eachcompartment of the drum will contain some of the material. The drum itself is of a relatively small diameter so that a slow rotation of the drum will'cause a rolling of the material on the screen. After the material has been spent it leaves the machine through the discharge outlet in the shaft wand from thenceit may be conducted to any desired place. During the rotation of the drum the finer particles of material in gradually increasing size will pass out through various screens 15, 16 and 17 to be segregated in the various compartments in the. bottom of the tank 18. The lower portion of the drum is entirely submerged in water so that all of the material in the drum is in a fluent. condition. Owing to surface tension the microscopic particles of gold tend to remain in suspension especially when there is a disturbance in the water no .matter how slight. The water beneath the drum is kept in quiescent condition and not subject to disturbance from the rotation of the drum due to the fact that the shield 32 confines the disturbance to the annular space between the drum and the shield. After the line particles of gold and gold ore have passed through the funnel 33 they are permitted to settle with little or no disturbance of the water medium in which they are suspended.

The entire machine is compact and of light weight as compared with the prior machines. It is designed for use in sandy localities in which the sand is found associated with small and minute particles of gold. 'As the rejected sand accumulates, the entire machine may readily be moved a sufficient distance to avoid the accumulation.

The material passing through the drum is maintained in a fluent condition. The rotation of the drum results ina rolling of the goldbearing sand with just sufiicient agitation to keep all but the heaviest particles of sand suspended in the water. When "the material is discharged with a certain amount of water, it may be conducted to a settling tank where 'the spent'sand may be separated by settling from the water. The objeet is to use the water over and over again for two reasons. In localities where there is a scarcity of water or where the water must be obtained from deep wells, the cost of conductingto have a small amount of gold which remains in suspension in the water. The water passing repeatedly through the drum thus accumulates gold in suspension and this gold on sufficient concentration will settle morereadily than it would if the gold occurs in smaller quantities.

Having thus described my invention'in such full, clear, and exact terms that its construction and operation will be readily understood by others skilled in the art to which it pertains, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a concentrator for separating ore from gold-bearing sand, a water tank having an open top, an intake tank for receiving water and gold bearing sand, means for maintaining a uniform water level in both of said tanks, a shaft extending across both of said tanks, said shaft being hollow in its end portions, a drum in said water chamber and secured to said shaft to rotate therewith, a screen surrounding said drum, disks dividing said drum into a plurality of compartments, a pickup device in said intake tank secured to said shaft to rotate therewith, said pickup device consisting of a pair of diametrically opposed scoops communicating with conduits for conducting the material to the hollow portion at the intake extremity of said shaft, a septum in the hollow portion at the intake extremity of said shaft for dividing the material picked up by said two scoops, the hollow portion at the intake extremity of said shaft being provided with two apertures for conducting the material into the first of the chambers of saiddrum, means associated with said disks for conducting the material in each compartment to the next adjacent compartment at every complete revolution of said drum, and means at the,

discharge end of said drum for discharging the spent material from the last of the compartments of said drum through the hollow portion at the outlet extremity of said shaft after the gold and gold ore has been extracted therefrom.

2. In a concentrator for separating gold from goldbearing sand, a washing tank, a horizontal shaft in the upper part of said tank, a foraminous drum secured to said shaft to rotate therewith, a receiving tank secured to said washing tank and to said shaft,lsaid shaft being tubular in both of its end portions to provide intake and outlet conduits for the passage of sand into and out of said drum, said intake conduit extending from said receiving tank into said washing tank, a rotatable scoop for picking up the sand from said receiving tank to be conducted through said intake conduit into said drum, the contiguous walls of said washing and receiving tanks being perforated and being spaced from each other to provide a chamber for receiving a filter layer of gravel, and a mechanism for discharging the spent sand, said mechanism including a septum in the discharge conduit of said shaft to divide said discharge conduit into two chambers, a. skimmer for dividing the spent sand, and a double scoop communicating with said skimmer and with the two chambers of said discharge conduit.

DANIEL B. CAVE. 

